/**
 * @file
 * Ethernet Interface Skeleton
 *
 */

/*
 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 *
 * This file is part of the lwIP TCP/IP stack.
 *
 * Author: Adam Dunkels <adam@sics.se>
 *
 */

/*
 * This file is a skeleton for developing Ethernet network interface
 * drivers for lwIP. Add code to the low_level functions and do a
 * search-and-replace for the word "ethernetif" to replace it with
 * something that better describes your network interface.
 */

#include "lwip/opt.h"
#include "lwip/def.h"
#include "lwip/mem.h"
#include "lwip/pbuf.h"
#include "lwip/timers.h"
#include "netif/etharp.h"
#include "err.h"
#include "ethernetif.h"
#include "stm32f4xx_eth.h"
#include "stm32f4xx_eth_conf.h"
#include "parameters.h"
#include <string.h>

//#include "core_cm4.h"

#define netifMTU                            (1500)
#define netifINTERFACE_TASK_STACK_SIZE		( 350 )
#define netifINTERFACE_TASK_PRIORITY		( configMAX_PRIORITIES - 3 )
#define netifGUARD_BLOCK_TIME				( 250 )
/* The time to block waiting for input. */
#define emacBLOCK_TIME_WAITING_FOR_INPUT	( ( portTickType ) 100 )

/* Define those to better describe your network interface. */
const char netName[] = {"Khomin"};

static struct netif *s_pxNetIf = NULL;
xSemaphoreHandle s_xSemaphore = NULL;

/* Ethernet Rx & Tx DMA Descriptors */
extern ETH_DMADESCTypeDef  DMARxDscrTab[ETH_RXBUFNB], DMATxDscrTab[ETH_TXBUFNB];

/* Ethernet Receive buffers  */
extern uint8_t Rx_Buff[ETH_RXBUFNB][ETH_RX_BUF_SIZE];

/* Ethernet Transmit buffers */
extern uint8_t Tx_Buff[ETH_TXBUFNB][ETH_TX_BUF_SIZE];

/* Global pointers to track current transmit and receive descriptors */
extern ETH_DMADESCTypeDef  *DMATxDescToSet;
extern ETH_DMADESCTypeDef  *DMARxDescToGet;

/* Global pointer for last received frame infos */
extern ETH_DMA_Rx_Frame_infos *DMA_RX_FRAME_infos;

static void ethernetif_input( void * pvParameters );
static void arp_timer(void *arg);

/**
 * In this function, the hardware should be initialized.
 * Called from ethernetif_init().
 *
 * @param netif the already initialized lwip network interface structure
 *        for this ethernetif
 */
static void low_level_init(struct netif *netif)
{
	uint32_t i;

	/* set netif MAC hardware address length */
	netif->hwaddr_len = ETHARP_HWADDR_LEN;

	/* set netif MAC hardware address */
	for(i=0;i<6;i++)
		netif->hwaddr[i] =  startParam.net.mac[i];

	/* set netif maximum transfer unit */
	netif->mtu = 1500;

	/* Accept broadcast address and ARP traffic */
	netif->flags = NETIF_FLAG_BROADCAST | NETIF_FLAG_ETHARP;

	s_pxNetIf =netif;

	/* create binary semaphore used for informing ethernetif of frame reception */
	if (s_xSemaphore == NULL)
	{
		vSemaphoreCreateBinary(s_xSemaphore);
		xSemaphoreTake( s_xSemaphore, 0);
	}

	/* initialize MAC address in ethernet MAC */
	ETH_MACAddressConfig(ETH_MAC_Address0, netif->hwaddr);

	/* Initialize Tx Descriptors list: Chain Mode */
	ETH_DMATxDescChainInit(DMATxDscrTab, &Tx_Buff[0][0], ETH_TXBUFNB);
	/* Initialize Rx Descriptors list: Chain Mode  */
	ETH_DMARxDescChainInit(DMARxDscrTab, &Rx_Buff[0][0], ETH_RXBUFNB);

	/* Enable Ethernet Rx interrrupt */
	{
		for(i=0; i<ETH_RXBUFNB; i++)
		{
			ETH_DMARxDescReceiveITConfig(&DMARxDscrTab[i], ENABLE);
		}
	}

#ifdef CHECKSUM_BY_HARDWARE
	/* Enable the checksum insertion for the Tx frames */
	{
		for(i=0; i<ETH_TXBUFNB; i++)
		{
			ETH_DMATxDescChecksumInsertionConfig(&DMATxDscrTab[i], ETH_DMATxDesc_ChecksumTCPUDPICMPFull);
		}
	}
#endif

	/* create the task that handles the ETH_MAC */
	xTaskCreate(ethernetif_input, (signed char*) "Eth_if", netifINTERFACE_TASK_STACK_SIZE, NULL,
			netifINTERFACE_TASK_PRIORITY,NULL);

	/* Enable MAC and DMA transmission and reception */
	ETH_Start();
}


/**
 * This function should do the actual transmission of the packet. The packet is
 * contained in the pbuf that is passed to the function. This pbuf
 * might be chained.
 *
 * @param netif the lwip network interface structure for this ethernetif
 * @param p the MAC packet to send (e.g. IP packet including MAC addresses and type)
 * @return ERR_OK if the packet could be sent
 *         an err_t value if the packet couldn't be sent
 *
 * @note Returning ERR_MEM here if a DMA queue of your MAC is full can lead to
 *       strange results. You might consider waiting for space in the DMA queue
 *       to become availale since the stack doesn't retry to send a packet
 *       dropped because of memory failure (except for the TCP timers).
 */
static err_t low_level_output(struct netif *netif, struct pbuf *p)
{
	static xSemaphoreHandle xTxSemaphore = NULL;
	struct pbuf *q;
	uint8_t *buffer ;
	__IO ETH_DMADESCTypeDef *DmaTxDesc;
	uint16_t framelength = 0;
	uint32_t bufferoffset = 0;
	uint32_t byteslefttocopy = 0;
	uint32_t payloadoffset = 0;

	if (xTxSemaphore == NULL)
	{
		vSemaphoreCreateBinary (xTxSemaphore);
	}

	if (xSemaphoreTake(xTxSemaphore, netifGUARD_BLOCK_TIME))
	{
		DmaTxDesc = DMATxDescToSet;
		buffer = (uint8_t *)(DmaTxDesc->Buffer1Addr);
		bufferoffset = 0;

		for(q = p; q != NULL; q = q->next)
		{
			if((DmaTxDesc->Status & ETH_DMATxDesc_OWN) != (uint32_t)RESET)
			{
				goto error;
			}

			/* Get bytes in current lwIP buffer  */
			byteslefttocopy = q->len;
			payloadoffset = 0;

			/* Check if the length of data to copy is bigger than Tx buffer size*/
			while( (byteslefttocopy + bufferoffset) > ETH_TX_BUF_SIZE )
			{
				/* Copy data to Tx buffer*/
				memcpy( (uint8_t*)((uint8_t*)buffer + bufferoffset), (uint8_t*)((uint8_t*)q->payload + payloadoffset), (ETH_TX_BUF_SIZE - bufferoffset) );

				/* Point to next descriptor */
				DmaTxDesc = (ETH_DMADESCTypeDef *)(DmaTxDesc->Buffer2NextDescAddr);

				/* Check if the buffer is available */
				if((DmaTxDesc->Status & ETH_DMATxDesc_OWN) != (uint32_t)RESET)
				{
					goto error;
				}

				buffer = (uint8_t *)(DmaTxDesc->Buffer1Addr);

				byteslefttocopy = byteslefttocopy - (ETH_TX_BUF_SIZE - bufferoffset);
				payloadoffset = payloadoffset + (ETH_TX_BUF_SIZE - bufferoffset);
				framelength = framelength + (ETH_TX_BUF_SIZE - bufferoffset);
				bufferoffset = 0;
			}

			/* Copy the remaining bytes */
			memcpy( (uint8_t*)((uint8_t*)buffer + bufferoffset), (uint8_t*)((uint8_t*)q->payload + payloadoffset), byteslefttocopy );
			bufferoffset = bufferoffset + byteslefttocopy;
			framelength = framelength + byteslefttocopy;
		}

		/* Prepare transmit descriptors to give to DMA*/
		ETH_Prepare_Transmit_Descriptors(framelength);

		/* Give semaphore and exit */
		error:

		xSemaphoreGive(xTxSemaphore);
	}

	return ERR_OK;
}

/**
 * Should allocate a pbuf and transfer the bytes of the incoming
 * packet from the interface into the pbuf.
 *
 * @param netif the lwip network interface structure for this ethernetif
 * @return a pbuf filled with the received packet (including MAC header)
 *         NULL on memory error
 */
static struct pbuf * low_level_input(struct netif *netif)
{
	struct pbuf *p= NULL, *q;
	uint32_t len;
	FrameTypeDef frame;
	uint8_t *buffer;
	__IO ETH_DMADESCTypeDef *DMARxDesc;
	uint32_t bufferoffset = 0;
	uint32_t payloadoffset = 0;
	uint32_t byteslefttocopy = 0;
	uint32_t i=0;

	/* get received frame */
	frame = ETH_Get_Received_Frame_interrupt();

	/* Obtain the size of the packet and put it into the "len" variable. */
	len = frame.length;
	buffer = (uint8_t *)frame.buffer;

	if (len > 0)
	{
		/* We allocate a pbuf chain of pbufs from the Lwip buffer pool */
		p = pbuf_alloc(PBUF_RAW, len, PBUF_POOL);
	}

	if (p != NULL)
	{
		DMARxDesc = frame.descriptor;
		bufferoffset = 0;
		for(q = p; q != NULL; q = q->next)
		{
			byteslefttocopy = q->len;
			payloadoffset = 0;

			/* Check if the length of bytes to copy in current pbuf is bigger than Rx buffer size*/
			while( (byteslefttocopy + bufferoffset) > ETH_RX_BUF_SIZE )
			{
				/* Copy data to pbuf*/
				memcpy( (uint8_t*)((uint8_t*)q->payload + payloadoffset), (uint8_t*)((uint8_t*)buffer + bufferoffset), (ETH_RX_BUF_SIZE - bufferoffset));

				/* Point to next descriptor */
				DMARxDesc = (ETH_DMADESCTypeDef *)(DMARxDesc->Buffer2NextDescAddr);
				buffer = (unsigned char *)(DMARxDesc->Buffer1Addr);

				byteslefttocopy = byteslefttocopy - (ETH_RX_BUF_SIZE - bufferoffset);
				payloadoffset = payloadoffset + (ETH_RX_BUF_SIZE - bufferoffset);
				bufferoffset = 0;
			}

			/* Copy remaining data in pbuf */
			memcpy( (uint8_t*)((uint8_t*)q->payload + payloadoffset), (uint8_t*)((uint8_t*)buffer + bufferoffset), byteslefttocopy);
			bufferoffset = bufferoffset + byteslefttocopy;
		}
	}

	/* Release descriptors to DMA */
	DMARxDesc =frame.descriptor;

	/* Set Own bit in Rx descriptors: gives the buffers back to DMA */
	for (i=0; i<DMA_RX_FRAME_infos->Seg_Count; i++)
	{
		DMARxDesc->Status = ETH_DMARxDesc_OWN;
		DMARxDesc = (ETH_DMADESCTypeDef *)(DMARxDesc->Buffer2NextDescAddr);
	}

	/* Clear Segment_Count */
	DMA_RX_FRAME_infos->Seg_Count =0;

	/* When Rx Buffer unavailable flag is set: clear it and resume reception */
	if ((ETH->DMASR & ETH_DMASR_RBUS) != (uint32_t)RESET)
	{
		/* Clear RBUS ETHERNET DMA flag */
		ETH->DMASR = ETH_DMASR_RBUS;
		/* Resume DMA reception */
		ETH->DMARPDR = 0;
	}
	return p;
}

static void ethernet_watchdog(void)
{
	/* When Rx Buffer unavailable flag is set: clear it and resume reception */
	if ((ETH->DMASR & ETH_DMASR_RBUS) != (uint32_t)RESET)
	{
		/* Clear RBUS ETHERNET DMA flag */
		ETH->DMASR = ETH_DMASR_RBUS;

		/* Resume DMA reception. The register doesn't care what you write to it. */
		ETH->DMARPDR = 0;
	}
}

/**
 * This function is the ethernetif_input task, it is processed when a packet
 * is ready to be read from the interface. It uses the function low_level_input()
 * that should handle the actual reception of bytes from the network
 * interface. Then the type of the received packet is determined and
 * the appropriate input function is called.
 *
 * @param netif the lwip network interface structure for this ethernetif
 */
void ethernetif_input( void * pvParameters )
{
	struct pbuf *p;

	for( ;; )
	{
		if (xSemaphoreTake( s_xSemaphore, emacBLOCK_TIME_WAITING_FOR_INPUT)==pdTRUE)
		{
			GET_NEXT_FRAGMENT:
			p = low_level_input( s_pxNetIf );
			if(p != NULL)
			{
				if (ERR_OK != s_pxNetIf->input( p, s_pxNetIf))
				{
					pbuf_free(p);
					p=NULL;
				}
				else
				{
					xSemaphoreTake(s_xSemaphore, 0);
					goto GET_NEXT_FRAGMENT;
				}
			}
		}
		ethernet_watchdog();
		vTaskDelay(10);
	}
}


/**
 * Should be called at the beginning of the program to set up the
 * network interface. It calls the function low_level_init() to do the
 * actual setup of the hardware.
 *
 * This function should be passed as a parameter to netif_add().
 *
 * @param netif the lwip network interface structure for this ethernetif
 * @return ERR_OK if the loopif is initialized
 *         ERR_MEM if private data couldn't be allocated
 *         any other err_t on error
 */
err_t ethernetif_init(struct netif *netif)
{
	LWIP_ASSERT("netif != NULL", (netif != NULL));

	if(sizeof(netName)<sizeof(netif->name))
		memcpy(&netif->name, &netName, sizeof(netName));

	netif->output = etharp_output;
	netif->linkoutput = low_level_output;

	/* initialize the hardware */
	low_level_init(netif);

	etharp_init();
	sys_timeout(ARP_TMR_INTERVAL, arp_timer, NULL);

	return ERR_OK;
}


static void arp_timer(void *arg)
{
	etharp_tmr();
	sys_timeout(ARP_TMR_INTERVAL, arp_timer, NULL);
}
